Social networking websites and applications have become widespread in the past decade. Social networks, such as Facebook and Instagram, enable users to send and receive a vast amount of content, such as text comments (e.g., updates, announcements, replies), digital photos, videos, audio files, web pages, news articles, and/or links thereto.
Given the vast amount of such content, social networks strive to efficiently provide content to a particular user that is relevant to the user, without overwhelming the user. But social networks face an ongoing challenge to determine which content to provide to a particular user at a particular time in a particular circumstance.